Sen. Obama boards his plane in Honolulu to head back to the campaign trail after visiting his ailing grandmother.

HONOLULU, Hawaii (CNN) - Democratic presidential nominee Barack Obama wrapped up almost two days worth of time away from the campaign trail Friday evening, as he finished spending time in Hawaii with his ill grandmother, 85-year-old Madelyn Dunham.

Earlier in the week, senior strategist Robert Gibbs described Dunham's condition as "very serious," but the campaign has not provided any further details.

Since arriving in Hawaii Thursday evening, Obama has kept a low profile, appearing within cameras' range only once, when taking a walk alone through his grandmother's neighborhood near Waikiki Beach on the island of Oahu.

Wearing jeans, a black short sleeved shirt, sandals, and sunglasses, Obama was described as "somber and sad," according to a pool report.

Obama's half-sister Maya Soetoro-Ng also spent time with the family Friday morning.

The Illinois senator has spoken fondly of his grandmother in the past. Dunham helped raise him during his teen years in Honolulu.

Obama heads to Nevada late Friday night, where he will resume his campaign schedule Saturday morning with a rally in Reno before heading to Las Vegas for an afternoon event and then to Albuquerque, New Mexico for one later in the evening.